Iron deficiency and low iron stores are prevalent in infants, adolescents, and women of childbearing age in both Western and developing countries. One cause of iron deficiency is the low iron bioavailability from foods, which is partly due to inhibiting factors in the diet, such as phytic acid and phenolic compounds. Other factors enhance iron absorption. These include muscle tissue, ascorbic acid and certain other organic acids.
Phytic acid is found mainly in the fibre fraction of cereals, vegetables and fruit. The inhibiting effect of phytic acid is due to the formation of insoluble complexes with iron at intestinal pH. A reduction in the content of phytic acid in those foods or a way to inhibit complex binding with iron would eliminate the problem with low iron absorption from foods that are rich in iron and which otherwise are regarded as healthy and nutritious. Phytic acid is hydrolyzed by phytases found in certain plants, microorganisms, and animal tissues. Most cereal phytases have a pH optimum in the range 5.0-5.6. By lowering the pH of foods the endogenous phytases in cereals and vegetables may be activated and thereby reduce the content of phytic acid, as in e.g. sourdough fermentation.
EP 1 003 532 describes the use of lactobacilli in the preparation of non-fermented enteral compositions for facilitating or increasing the absorption of minerals from the diet. The only experiments performed therein in supporting said claimed absorption is an in vitro model of calcium responses or transportation of calcium using Caco-2 intestinal lines (a carcinogenic cell line).
In accordance with the present invention metal/metal ion absorption has been performed in an in vivo study in humans. It has surprisingly been found that not all lactobacilli have the desired absorption as claimed in EP 1 003 532. It has further been found that certain specific strains of Lactobacillus plantarum achieve a surprisingly good absorption of said metals/metal ions in the body.